Gastroesophageal reflux disease (GERD) is estimated to occur in approximately 50% of normal term infants at the age of 2 months; however approximately 1% still have reflux at one year of age. Reflux is exacerbated in preterm infants, since gastric movements, such as motility and emptying, are lower so that reflux and related symptoms are not as easy to detect. Indeed, many symptoms currently considered to be GERD-related (e.g., apnea) are likely not causally related.
The majority of current efforts to treat GERD in infants involve antacids and increasing gut motility. However, few properly designed prospective studies, at least in infants, have shown efficacy of these treatments. Indeed, antacid treatment in preterm infants may promote adverse overgrowth of bacteria and predispose them to the development of necrotizing enterocolitis.
Similarly in adults, a putative diagnosis of GERD leads to (at least initial) empirical treatment with proton pump inhibitors, which treat the acidity of the refluxate, but not with medications designed to increase gut motility or suppress reflux. Further, because non-acid reflux is difficult to detect and has few if any effective treatments, non-acid reflux is generally ignored in the therapy of adult reflux. Use of an impedance monitor to detect non-acid reflux has been proposed as a new gold standard in the diagnosis and treatment of adult reflux, but significant problems remain with this diagnostic modality (vide infra).
Lower esophageal sphincter (LES) tone is historically considered to be involved in GERD and a focus of treatment. However, resting LES tone is not maturity related since resting LES at all ages exceeds intragastric pressure. Further, LES pressure does not correlate with GERD symptoms additionally making LES related treatments less than optimal.
Currently, the pH probe is the “gold standard” for the detection of reflux symptoms and diagnosis of acid reflux. However, in addition to being an invasive device, where the probe must be internalized in order to contact acid gastric materials, reflux has both acidic and non-acid occurrences, especially in preterm infants. Thus because a pH probe does not accurately measure non-acidic reflux this “gold standard” fails to detect non-acidic reflux. Therefore there is a lack of capability of detecting reflux in a non-invasive manner as well as a greater lack of capability for measuring non-acid reflux. Detection of non-acid reflux is especially important in preterm infants whose stomach acidity is less than in older children and adults.
In conclusion there is a lack of a diagnostic tool for detecting both acidic and non-acidic reflux symptoms for use in detecting reflux and for diagnosing GERD in order to begin providing effective reflux treatments for patients of any age.